SF 121 
.M85 
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The Estimation 
of Condition in Cattle, 



BY 



J. ALAN MURRAY, B.Sc, 

Lecturer in Agricultural Chemistry at Utiiversity 
College, Reading. 



Reading : 
Charles Elsbury, 25, ^Iill Lane. 

1914. 



PREFACE. 



The following paper was read at the Meeting of the British 
Association in Australia this year, but owning to the outbreak of 
war and other causes it has not been reported in the papers. 
This is the more regretable because the paper was not designed 
to settle the question, but to open it — to invite criticism and 
co-operation. The author has, therefore, deemed it advisable to 
reprint it in extenso with this object in view. He will welcome 
any public or private criticism either of the general proposition 
or of details, such as the best method of making the measure- 
ments, expressing results, etc. ; and he will be extremely glad to 
receive or to have his attention called to any data bearing on 
the subject. 



J. A. M. 



Beading, 

24th October, 1914. 



By transfer 

APR 29 191^ 



p 






Win O^stimatioit of ConDition in Cattk, 

BY 

J. ALAN MUEEAY, B.Sc, 

Lecturer in Agricultural Chemistry at University College, 
Heading. 



THE verba] terms used by fanners to describe the "condition " 
of animals, e.^., " fat," " half-fat," "store," etc., are vague 
and indefinite. They are, however, in common use, and 
it would be futile to suggest that they should be changed or 
abandoned ; but it is not, perhaps, inopportune to enquire 
whether a more definite signification might be ascribed to them. 
In order to ascertain what these terms connote in the ordinary 
language of those who use tliem, it is convenient first to con- 
sider the noun (condition) before attempting to deal with the 
adjectives. 

The condition of cattle is usually judged by the appearance 
of the animals, the flexibility of the skin and so on ; but these 
indications are not entirely satisfactory. The vagueness of the 
terms used to describe condition is, ^lo doubt, due in large 
measure to the difficulty of judging it. The only exact method 
of expressing all the various degrees of condition is by means of 
numerical values, and if these are to be employed, the condition 
must be determined in a different manner. 

The live weights are expressed by njimbers. These vary with 
the condition of the animals, but they cannot be used as a 
general test of condition because they also vary with the size 
(extension of the frame). Thus, if two animals were in the 
same condition but one of them was bigger than the other it 
would weigh heavier. If two animals were of the same size 
but one of them was in better 'condition than the other it 
would weigh heavier. But if two animals w^ere of the same 
size and in the same condition they would have the same 
w^eight. 



It appears, therefore, that the term condition, as used in this 
connection, may be interpreted to mean that quality which is 
measured by the ratio of hve weight to size. This view is more 
concisely expressed by the equation 



M 



where M is the Hve weight, S is the size, and C is a number 
which expresses the condition of the animal. 

This proposition is not entirely novel, but, so far as the author 
is aware, it has not previously been expressed in exactly this 
form. It is well known that the weight of dressed carcass can 
be estimated, with more or less accuracy, from the size as 
determined by measurement of certain dimensions, viz., the 
length and girth of the animal. Several rules are given by 
which the result may be worked out. Most of them, however, 
apparently aim at simplicity rather than accuracy. Only one 
of them attempts to take into account the condition of the 
animal. This rule is generally rendered as follows : " the girth 
squared multiplied by the length (both in feet) and the product 
multiplied by a factor (-23, -24, -25, or -27) according as the 
animal is moderately fat, fat, prime fat, or very fat, gives the 
weight of dressed carcass in imperial stones." Tf the factor 
which varies with the condition of the animal be designated by 
the symbol C and the length, girth and live weight by L, G and 
M respectively, the rule may be expressed in the form of an 
equation as follows : 

M - C X L X G2 

It is generally considered that this rule, though better than 
any of the others, is not altogether trustworthy. This is 
attributable partly to the difficulty of making exact measure- 
ments and partly to the fact that the rule itself is radically 
unsound. Thus, if the factor C be evaluated in terms of the 
others by the usual methods we obtain 

M 



L G2 



Stated in this form it will be seen that the equation involves 
a contradiction in terms. When an animal becomes fat the 
girth increases to a certain extent (and C should become greater) ; 
but since G occurs in the denominator, any increase in the 
value of G tends to diminish that of C ; and since G is squared, 
the error thus introduced may be considerable. 



The object of the foregoing discussion was not primarily to 
criticise this particular rule, but to show that the proposition 
C = M/S is an accepted idea. Incidentally it appears that S 
may be rendered by L x G (or some function of the same) 
provided that G represents the girth in store condition ; in the 
case of fat beasts some allowance must be made for the increase 
of girth due to fattening. The equation may, therefore, be 
written provisionally as follows : 

M 



L(G-X) 



In order to test the matter, and if possible to determine X, 
observations of the lengtli, girth and live weight were made upon 
a number of animals, and these data, together with certain 
others derived from them, are given in the table below. 



Table I. 
Store Cattle. 



Mark. 

371 
370 
359 
365 



Live 
Weight. 

(M) 



Length. 
(L) 



pounds. inches. 
882 52 



924 
952 
952 



52 
48 
46 



Girth. 


G 
L 


inches. 
72 


1-385 


72^ 


1-394 


71 


1-479 


70^ 


1-533 



16-96 12-25 
17-77 I 12-74 



19-83 
20-69 



13-41 
13-53 



Difference. 
M M 



4-71 
5-03 
6-42 
7-16 



Moderately Fat Beasts. 



318 


1148 


48 


77 


1-604 


23-91 


14-91 


9-00 


302 


1232 


54 


78 


1-444 


22-81 


15-80 


7-01 


305 


1400 


57 


82 


1-439 


24-56 


17-07 


7-49 


185 


1428 


58 


81 


1-396 


24-62 


17-63 


6-99 



The data are arranged in the order of the live weights, and as 
it happens that this is practically the same as the order of 
fatness when ultimately worked out it might be inferred that 
the live weight is, by itself, a reliable index of condition. It is 
true that when animals are fully grown any change in their 



6 

weight (+ or — ) indicates a change of condition and is an exact 
measure of the same, because the size remains constant. This, 
however, does not apply to growing animals, nor does it enable 
us to compare one with another. It will be seen, on reference 
to the table, that Nos. 359 and 365 have exactly the same weight, 
but the latter is 2in. shorter and ^in. less in girth, i.e., it is 
altogether a smaller animal and could not, therefore, have the 
same weight unless it were in better condition. 

It may be assumed that in any given animal the ratio of girth 
to length is a constant quantity, i.e., that it is not affected by 
growth as apart from fattening, and that the length is indepen- 
dent of condition. If this be so, the size of the animal may be 
gauged by the latter dimension alone, aud any change in 
condition (+ or — ) will be determined by the variation in the 
ratio M/L. It should be possible, therefore, in this way, to 
compare the condition of the animal at all stages of growth, but 
not necessarily to compare one animal with another. 

When two or more animals are to be compared it cannot be 
assumed that the ratio of girth to length is the same in all. 
The few examples given in the table show that it is not, and the 
ratio M/L cannot, therefore, be regarded as a reliable index of 
condition for the purpose of comparison. Thus, if two animals 
were of the same length, but of unequal girth, that which had 
the greater girth would weigh heavier and would show a higher 
ratio of live weight to length, though there was no difference in 
condition. The variation in the ratio G/L is, however, less than 
might be supposed. In the case of the store animals it ranged 
from 1-385 to 1*533, and in the case of the fat beasts from 1-396 
to 1-604. The ratio M/L does, therefore, reflect the condition, 
and may even be regarded as a fairly approximate estimate of it. 

Eeferring again to the table, it will be seen that the ratio 
M/G is always less than M/L, because, of course, G is always 
greater than L, but it varies in much the same manner. The 
order of fatness judged by either of these two ratios is the same. 
At first sight it appears as if the condition were reflected with 
equal accuracy by either, but as G is not independent of condi- 
tion it is clear that such is not the case. It will also be noticed 
that though the ratio M/G varies in much the same manner as 
M/L, it does not vary in the same degree. The difference 
between them is greater in the case of fat beasts than in stores. 
This is probably attributable to the increase in girth which takes 
place when the condition of the animal improves. Any increase 
in the value of G diminishes the ratio M/G and so tends to 
increase the difference between M/L and M/G. 

An attempt to estimate the increase in girth in this way 
showed that when the animals are moderately fat it is about 



four per cent. ; but when the method was appHed to similar 
data from other sources it was found to be unsatisfactory. 

Upon consideration, it seems clear that the increase must be 
some fractional part or percentage of tlie girth observed, i.e., it 
must be I G/100. Now the ratio M/L varies with the degree of 
fatness, and, though not itself a reliable test of condition, it 
should afford a fairly close approximation to the value of I. 
Thus, when the animal is in store condition, i.e., when there is 
no increase due to fattening, M/L — 17, and since, in that case, 
I is 0, I = (M/L — 17). Again, when the animal is moderately 
fat, M/L = 25, and since, in that case, the value of I is about 4, 
i.e., about half the difference between 25 and 17, I = 0*5 
(M/L - 17). The expression G/200 (M/L - 17), therefore 
represents the increase in girth due to fattening, and the original 
girth — which the animal would have had had it remained in 
store condition — may be found by subtracting that amount from 
the girth observed. In short, the expression G/200 (M/L — 17) 
represents the value of X in the provisional formula (page 5). 

If the value of C be now worked out in each case it wall be 
found that owing to the accident of the particular units em- 
ployed (pounds and inches) the results are fractional numbers. 
For purposes of comparison it is more convenient to take the 
condition of the leanest animal — assumed to be a typical store — 
as 100, and that of the others pro rata. The factor required for 
this purpose is 424-4. The revised formula may now be written 
as follows : 

424-4 M 
C = 



200 



(M/L - 17) 



The original girth and present condition of each of the animals 
calculated by this formula is shown in the table below. 

Table II. 



Stores. 



Fat Beasts. 



No. 


Girth 
Observed. 


Original 
Girth. 


Condition. 


No. 


Girth 
Observed. 


^r^ Condition. 


371 
870 
359 
365 


72 
72-5 
71 
70-5 


72 
72-3 
70 
69-2 


100-0 
104-5 
120-2 

129-2 


302 
318 
305 
185 


77 
78 
82 
81 


75-7 127-4 
74-3 136-5 
78-9 132-1 
77-9 134-1 



8 

It is noticeable that according to these results, Nos. 359 and 
365, though classed as stores, are in nearly as good condition as 
those classed as fat, and there seems to be no reason to doubt 
the truth of this inference. The policy of maintaining an animal 
in the condition of No. 365 at that stage of growth cannot be 
discussed here ; but it may be said in passing that one of the 
arguments by which it is sometimes supported — the more rapid 
increase in the live weight of young animals — seems to be 
beside the question. The additional weight which a young 
animal puts on is mainly, if not entirely, due to growth. There 
is nothing to show that a young animal puts on tj^ue fattening 
increase more rapidly or more easily than one which is fully 
grown. In the absence of some means of estimating condition 
—such as that now proposed — the question is a difficult one to 
investigate. 

From a purely practical standpoint the condition of animals 
is of interest chiefly in regard to its bearing on the question of 
valuation. When animals are sold by weight, the rate by which 
the price is determined is fixed at so much per cwt., according 
to the condition of the animals. This rate, of course, fluctuates 
in accordance with the laws of economics, but it is suggested 
that if an animal whose condition is 100 be worth 28/- per cwt., 
then one whose condition is 130 should be worth 36/5 per cwt. 
In other words, if the rate for the typical store be 28/- that for 
any other animal of known condition should be 0*28 C. 

When the rate per cwt. is fixed it is only necessary to multiply 
by the live weight (in cwts.) to find the actual price. If the 
live weight be given in pounds, this would be expressed as 
follows : 

0-28 C X M 

P = 

112 

or, if the formula be substituted for C : 

0-28 X 424-4 X M X M 1-061 M^ 



P = 



112 L 'g - ■ (M/L - 17)1 L-'g (M/L - 17)^- 

l 200 ) i 200 ) 

The rate per cwt. and corresponding price of each of the 
animals, calculated by this formula, are shown in Table III. 

It will be seen that No. 302, though classed as fat, is valued 
at a slightly lower rate per cwt. than No. 365, which is classed 



as store. The former, however, is estimated to be worth over 
£■1 more than the latter because, of course, it is much bif^f>er. 



Table III. 



Stores. 



Fat Beasts. 



No. 


Rate 
per Cwt. 


Price. 

£ s. a. 


No. 
302 


Rate 
per Cwt. 


Price. 
£ s. (1. 


371 


28/- 


11 6 


35/8 


19 12 5 


370 


29/3 


12 1 5 


318 


38/3 


19 11 9 


359 


33/8 


14 6 1 


305 


37/- 


23 2 6 


365 


36/2 


15 7 6 


185 


37/6 


23 18 9 



It was not originally the intention of the author to enter upon 
the discussion of such practical matters at all. The object was 
merely to find some means of testing the condition for purposes 
of scientific experiment. Oxen are not infrequently put up to 
fatten before they are fully grown, and in such cases any 
inferences drawn from the increase in live weight must be of 
doubtful validity unless a distinction is made between true 
fattening increase and that due to growth. 

The question of maintenance rations is also involved. The 
feeding standards quoted in the text-books are presumably based 
on the requirements of animals in "store" condition, whatever 
that may be. It is tolerably certain, however, that more food 
is required to maintain an animal in the fat or half-fat condition. 
If the rations of a fat beast were reduced to what is required to 
maintain it in store condition it would "go back," i.e., it would 
lose weight and become thin again. At all events, the results 
obtained by different observers cannot be regarded as strictly 
comparable unless there be some assurance that the animals 
were at least approximately in the same condition. The ques- 
tion of maintenance rations is not only of considerable interest 
in itself, but it is of fundamental importance in connection with 
all feeding trials for any purpose whatever. 

Though not favourably situated for collecting data of this 
kind, the author has obtained a few additional examples from 
three different sources. From the figures given in Tal)le IV it 
will be seen that these broadly confirm the conclusions previously 
arrived at. 

Special importance is attached to the results in group \ 
(milk cows) because the observations were made by a trusted 
'■'colleague in the presence of the author, and every precaution 

* Mr. Sidney Pennington, B.Sc, M.R.C.V.S., Lecturer on Agriculture 
and IManager of the Farm at University College, Reading. 



10 

was taken to ensure accuracy. The condition of the animals 
was described by practical experts in the following terms : the 
bull, very fairly fat ; Rose, very good condition ; Cherry, good 
condition ; Countess, medium fair ; Duchess, rather poorer, but 
above the average for milk cows. It was considered that the 
figures very fairly indicated the relative condition of the animals. 



Table IV. Additional Examples. 
Group A. — Milk Cows. 



Mark. 


Live 
Weight. 


Length. 


Girth 
Observed. 


M 

L 


M 
G 


Original 
Girth. 


* 
Condition. 


Duchess 


pounds. 
1116 


inches. 
52 


inches. 
72-5 


21-46 


15-39 


inches. 
70-9 


128-5 


Countess 


1372 


59 


78 


23-25 


17-60 


75-6 


130-6 


Cherry 


1456 


58 


79-5 


25-10 


18-31 


76-3 


139-6 


Rose 


1680 


60 


86 


28-00 


19-53 


81-3 


146-2 


Bull 


2044 


67 


89 


30-51 


22-97 


83-0 


156-0 



Group B. — Stores. 



1 


920 


50-5 


71 


18-21 


12-96 


70-6 


109-5 


2 


920 


50-5 


72-5 


18-21 


12-70 


72-1 


107-3 


3 


840 


49-5 


68 


16-95 


12-35 


68-0 


105-9 


4 


896 


530 


72 


16-90 


12-39 


72-0 


99-6 


5 


808 


51-0 


68 


15-84 


11-88 


68-4 


98-5 


6 


808 


44-0 


68 


18-36 


11-88 


67-6 


115-9 



Group C. — Fat Cows. 



1 


1225 


50-5 


84 


24-25 


14-58 


81-0 


127-1 


2 


1230 


49 


84 


25-10 


14-64 


80-6 


132-2 


3 


1079 


48 


74-5 


22-49 


14-48 


72-5 


131-7 


4 


1129 


48 


72 


23-51 


15-68 


69-7 


143-3 


5 


1235 


50 


77-5 


24-70 


15-93 


74-5 


140-7 



* Compared with No. 371 in Table I taken as 100. 

In the case of No. 5, group B, it will be noticed that the 
condition is less than 100. In other words it is slightly inferior 
to that of No. 371, which was selected merely because it was 
the leanest in the first set of data obtained. If this animal be 



11 

accepted as a truly typical store, then the condition of No. 5 is 
below par. The average condition of the animals in group B 
is 106, and if that be taken as the normal (100) then the con- 
dition of No. 371 would be 94-3, and that of No. 5 only 92-9. 
The only positive inference that can be drawn is that more data 
are required. 

In the case of the milk cows (group A) the length was 
measured between two vertical standards, one of which was 
placed against the point of the shoulder and the other in line 
with the extremity of the buttock. In the other cases it was 
measured by means of a tape along the back in the usual way. 
The latter method is far from satisfactory. It is possible that 
the several observers did not determine the points in exactly the 
same manner. In that case the different sets of data would not 
be strictly comparable one with another, though each set might 
be consistent in itself. 

So far as it goes, however, the evidence is favourable to the 
principle of the method ; but, for the present, the formula proposed 
(page 7) is offered merely as a hypothesis to be tested. The 
essential conditions of such a test are (1) to devise some method 
or apparatus for the measurement of length by which exactly 
the same results would be obtained by different observers, and 
(2) to accumulate a considerable mass of data relating to typical 
store and fat animals of different ages and breeds. 

Neither of these conditions appears to present any insuperable 
difficulties, but they require the co-operation of expert judges of 
cattle whose words would be accepted. It is not anticipated 
that in order to obtain reliable results it will be found necessary 
to take very elaborate precautions such as would render the 
method useless to ordinary farmers ; but even should this prove 
to be the case, the method, if definitely established, w^ould still 
be invaluable to scientific investigators and to those who are 
called upon to advise farmers. 



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